'79 XS650 Build project.

2BallCane

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So, aside from my timing issue, I think I know why my M-unit is blinking when the engine is revved. Pretty sure a few of you warned me about the fact of combining LED's with a PMA setup. I think that There's not enough resistance between the battery and M-unit and LED's. So I have a few options to correct this.

1. Change back to stock headlight, but it would reduce visiblity
2. Wire in a Load resistor between the M-unit and Battery.
3. Wire in load resistors at each LED
4. Wire in a Incandescent bulb between battery and M-unit to suck up the juice.

the HHB PMA is putting about 14.8v to the battery, so I would like to lower that to 13.5-14v.

I open to suggestions/ideas, or corrections to my assumptions. Thanks
 

Jim

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the HHB PMA is putting about 14.8v to the battery, so I would like to lower that to 13.5-14v.
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2BallCane

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Going by that statement, I assumed you meant the LED's on the M-unit. Is that not the case?
No, the LED's on the M-unit work just fine. But every other light on the bike is LED, so it's not consuming nearly as much power as the OEM lights. I think this is why there is a certain light on the M-unit that flashes when I rev into higher RPM's. I think the power is too much for the lights, and the M-unit is warning that it's a problem.
 

Jim

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No, the LED's on the M-unit work just fine....
there is a certain light on the M-unit that flashes when I rev into....
Maybe you could tell us exactly what light is flashing and what, if anything is attached to it? A cryptic "certain light" is not making your problem clear... at least not to me.

You said you were warned about LED's and PMA's. That warning pertains to current draw. A PMA put's out max current, regardless of demand. LED's require less current. This means your regulator is working overtime dumping that excess current to ground. This shortens the life of the regulator. That is the warning about mixing PMA's and LED's The warning has nothing to do with lights flashing or LED's not working properly... they will work just fine.

Put another way.... say an LED requires 2amps to work properly. It will draw that 2amps and nothing more. You could put an alternator on there that puts out 100amps and the LED will still only draw the 2 it requires and nothing more.
 

2BallCane

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Maybe you could tell us exactly what light is flashing and what, if anything is attached to it? A cryptic "certain light" is not making your problem clear... at least not to me.

You said you were warned about LED's and PMA's. That warning pertains to current draw. A PMA put's out max current, regardless of demand. LED's require less current. This means your regulator is working overtime dumping that excess current to ground. This shortens the life of the regulator. That is the warning about mixing PMA's and LED's The warning has nothing to do with lights flashing or LED's not working properly... they will work just fine.

Put another way.... say an LED requires 2amps to work properly. It will draw that 2amps and nothing more. You could put an alternator on there that puts out 100amps and the LED will still only draw the 2 it requires and nothing more.
I know what you're saying. I need something to suck up that extra *amps* being put out by the PMA. The light that is flashing is the Bluetooth light, but I have a Basic unit. So I don't know if it's warning me or just sucking up the extra juice. My horn has never gone off to warn of high voltage.
 

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Jim

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Well, your basic unit doesn't come with bluetooth, so that light flashing is a mystery.... it shouldn't have any power to it.
Pretty sure that it doesn't have anything to do with excess current though. At least the manual doesn't say anything about that. I think I'd shoot the manufacturer an email and ask why it's flashing when there's no bluetooth installed.

I need something to suck up that extra wattage being put out by the PMA.
Right now the regulator is (should be) doing exactly that.
Just be aware that your electrical system should work just fine with the PMA/LED combo.... including the M-unit. The only downside is the overworked regulator.... and it's shortened life.
 

JesseeS

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I know what you're saying. I need something to suck up that extra *amps* being put out by the PMA. The light that is flashing is the Bluetooth light, but I have a Basic unit. So I don't know if it's warning me or just sucking up the extra juice. My horn has never gone off to warn of high voltage.
I have heard of other people having issues where the lights were flashing (not just the Bluetooth one). Their issues that caused this were 1. Bad ground 2. Bad battery 3. A reg/rec overcharging their battery. You can try to hook up something to use that extra power and see if that's what it is since it's easily reversible but I would definitely contact them since there's nothing in the paperwork directly speaking of bluetooth led flashing.
 

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Full disclosure.... I don't have an M-unit nor ever played with one. I do have a little elec. experience though, so I'm shootin' from the hip here.
I do plan on using one some day though, so I follow along on any thread dealing with 'em.
 

Jim

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Their issues that caused this were 1. Bad ground
That was my first thought also. I think I'd add an extra ground wire directly from the frame to the M-unit and see if that helps.... even if just a temporary wire to see.
 

2BallCane

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So I contacted Revival Cycles about it, as well as Motogadget about the light blinking. It only started blinking when the bike runs at certain RPM's. I even bought a brand new AGM battery since the other was old and somewhat dead. The battery is better for starting, but the blinking light still persists. I just don't want to damage the M-unit.
 

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So I contacted Revival Cycles about it, as well as Motogadget about the light blinking. It only started blinking when the bike runs at certain RPM's. I even bought a brand new AGM battery since the other was old and somewhat dead. The battery is better for starting, but the blinking light still persists. I just don't want to damage the M-unit.
Have you painted/ powdercoated the frame? I would double check where you are grounded. Maybe take a small wire wheel to the areas just to be sure it's solid bare metal (can always touch up after). If not that either then I would just hold off until you hear from motogadget. I understand not wanting to damage it it's not exactly cheap equipment
 

2BallCane

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That was my first thought also. I think I'd add an extra ground wire directly from the frame to the M-unit and see if that helps.... even if just a temporary wire to see.
I have the M-Unit grounded right to the frame with a separate wire and that goes to the same ground point as the battery. The ?
M-Unit has a main fuse between it and the battery. The MOSFET Rec. Goes directly to the battery
 

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2BallCane

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Have you painted/ powdercoated the frame? I would double check where you are grounded. Maybe take a small wire wheel to the areas just to be sure it's solid bare metal (can always touch up after). If not that either then I would just hold off until you hear from motogadget. I understand not wanting to damage it it's not exactly cheap equipment
I took a wire wheel to each grounding point to ensure good contact, then measured resistance. I ran a direct ground wire from the MOSFET Rec to the same point as the M-Unit and battery.
 

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The M-unit is bolted inside the toolkit area. all the grounds lead to the same point to eliminate resistance. I even ran a dedicated ground line from the handlebar switches to the headlight housing, and from there back to that same ground point. The only thing i can think is that the LED's are having issue accepting the extra voltage, and the M-unit recognizes that. I originally had a 30A fuse between the M-unit and the battery, but replaced it with a 15A just to be safe
 

Jim

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The only thing i can think is that the LED's are having issue accepting the extra voltage, and the M-unit recognizes that.
If you mean the headlight LED (?) then just unplug it and see if the bluetooth light still acts up.
If you think it's the PMA, unplug it, just run off the battery... rev the bike and see if it still flashes.
You can turn off... unplug or disconnect anything going to the M-unit and see if if stops the flashing.

One way to narrow it down to something specific.
 

2BallCane

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If you mean the headlight LED (?) then just unplug it and see if the bluetooth light still acts up.
If you think it's the PMA, unplug it, just run off the battery... rev the bike and see if it still flashes.
You can turn off... unplug or disconnect anything going to the M-unit and see if if stops the flashing.

One way to narrow it down to something specific.
How would I separate them? the positive cable that runs from the PMA relay runs into the M-unit Ignition output to provide power. Do i just remove the positive MOSFET cable from the battery? It's going to have to wait until later this week. I still need to correct the timing
 

Jim

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I would unplug the stator from the regulator. That would configure your bike exactly like it normally is. The only difference is no charge would ever go to the regulator.... just like the bike isn't running.
 

2BallCane

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I'll give that a try when I get some time this week. If it works, then what should I do to correct the problem?

If it doesn't work, what step should I take after that?
 
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